Borneo to be wild: Watching the whirling carousel of wildlife in Sabah and Sarawak

It is famously home to several of the world's most spectacular endangered animals, too, including the Sumatran rhino and Bornean clouded leopard.

Most visitors hope to come face to face with the region's most iconic animal, the cuddly orang-utan. But I must confess that orang-utans don't really do it for me. With their big, baby eyes and all that ginger fluff, they are far too cute.

There's a much more interesting primate to be found in the jungles of Borneo. You don't have to hike for hours to see it, either...

The base for my animal adventure was the brand-new YTL luxury resort on Gaya Island, within the Tunku Abdul Rahman Conservation Park in Sabah. Sabah and Sarawak states make up Malaysian Borneo, representing 27 per cent of the island. The rest is split between Brunei and Indonesia.

Gaya Island Resort is reached via the airport at Kota Kinabalu. Then it's a 15-minute speedboat ride from nearby Sutera Harbour. The resort is tucked along the coastline facing Malohom Bay, with lovely views over sea, beach or Mount Kinabalu, at 13,435ft the tallest mountain in South East Asia. Behind it, there is acre after acre of unspoilt rainforest where few humans have trodden.

The resort's resident naturalist Justin has, with the support of Sabah Parks, been a-foraging to see what wildlife lives there, and takes guests on hikes - hard and not so hard - through the dark jungle in the hope of finding such fabulous creatures as flying squirrels and bearded pigs (I love that you get exactly what it says on the tin).

Surprisingly, and hugely excitingly, it's also home to the animal I had come to see, the extraordinary, endangered proboscis monkey.

There are no prizes for guessing why the Nasalis larvatus is so called. The monkeys, particularly males, have extremely large noses - in elderly animals it can reach 7in, or a quarter of their body length.

Found only in Borneo, proboscis monkeys also go by the Malay name orang belanda, meaning 'Dutchman', as Indonesians noted that Dutch colonisers often had a similarly large abdomen and hooter. How rude!

In fact, both sexes appear to have pot bellies, thanks to the expansive digestive systems needed to process their diet of leaves and unripe fruit. One of these monkeys wouldn't thank you for a ripe banana, explained Jason, as eating it would produce flatulence on an epic scale in the poor creature.

But the best thing about proboscis monkeys is the way they swim. Not just a quick monkey-paddle like many primates - they are capable of swimming 65ft underwater. And they have webbed paws. So they should have been very happy when, halfway through my jungle walk, the heavens opened and the heaviest rain I've seen fell and drenched us. We saw nothing, though Justin did try to get me excited about a rather static money plant stick-insect clinging to some bark.

Fortunately, Plan B was to travel two miles south on the main island to join the Garama Wetland River Cruise in the Kuala Penyu region. We had been aboard for only five minutes, not even out of the narrow channels joining the river proper, when I smelt something ... peculiar.

Proboscis monkeys do not have a pleasant natural aroma, sadly, but that does make them easier to find. And there, right by the water's edge, were handfuls of them, including a male.

They are normally found in groups of four to 20, either all bachelors or just one rather smug boy with a lot of girlfriends.

Their fur is extraordinarily colourful - orange, red-brown and yellowish in patches; their faces are orangey-pink, and they make incredible noises - honks, squeaks, roars and snarls.